using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using ET;
using UnityEngine.Networking;

namespace BM
{
    /// <summary>
    /// 验证脚本
    /// </summary>
    public static class VerifyHelper
    {
        public static string GetMd5Hash(string filePath)
        {
            byte[] data = MD5.Create().ComputeHash(Encoding.UTF8.GetBytes(filePath));
            StringBuilder sb = new StringBuilder();
            foreach (byte t in data)
            {
                sb.Append(t.ToString("x2"));
            }
            return sb.ToString();
        }
        
        /// <summary>
        /// 得到一个路径下文件的CRC32
        /// </summary>
        internal static async ETTask<uint> GetFileCRC32(string filePath)
        {
            uint fileCRC32;
            ETTask tcs = ETTask.Create(true);
            using (UnityWebRequest webRequest = UnityWebRequest.Get(filePath))
            {
                webRequest.timeout = 0;
                UnityWebRequestAsyncOperation weq = webRequest.SendWebRequest();
                weq.completed += o =>
                {
                    tcs.SetResult();
                };
                await tcs;
#if UNITY_2020_1_OR_NEWER
                if (webRequest.result == UnityWebRequest.Result.Success)
#else
                if (string.IsNullOrEmpty(webRequest.error))
#endif
                {
                    byte[] data = webRequest.downloadHandler.data;
                    fileCRC32 = VerifyHelper.GetCRC32(data);
                }
                else
                {
                    fileCRC32 = 0;
                }
            }
            return fileCRC32;
        }

        public static uint GetCRC32(byte[] bytes)
        {
            uint iCount = (uint)bytes.Length;
            uint crc = 0xFFFFFFFF;
            for (uint i = 0; i < iCount; i++)
            {
                crc = (crc << 8) ^ CRCTable[(crc >> 24) ^ bytes[i]];
            }
            return crc;
        }
        
        /// <summary>
        /// 创建加密过的数据
        /// </summary>
        public static byte[] CreateEncryptData(string filePath, string secretKey)
        {
            byte[] encryptData;
            char[] key = secretKey.ToCharArray();
            using (FileStream fs = new FileStream(filePath, FileMode.Open))
            {
                encryptData = new byte[fs.Length];
                fs.Read(encryptData, 0, encryptData.Length);
                for (int i = 0; i < encryptData.Length; i++)
                {
                    encryptData[i] = (byte)(encryptData[i] ^ key[i % key.Length]);
                }
            }
            return encryptData;
        }
        
        /// <summary>
        /// 异步获取解密的数据(无密钥的情况下直接获取数据)
        /// </summary>
        internal static async ETTask<byte[]> GetDecryptDataAsync(string filePath, WebLoadProgress loadProgress = null, char[] secretKey = null)
        {
            byte[] encryptData;
            ETTask tcs = ETTask.Create();
            using (UnityWebRequest webRequest = UnityWebRequest.Get(filePath))
            {
                UnityWebRequestAsyncOperation weq = webRequest.SendWebRequest();
                if (loadProgress != null)
                {
                    loadProgress.WeqOperation = weq;
                }
                weq.completed += (o) =>
                {
                    tcs.SetResult();
                };
                await tcs;
#if UNITY_2020_1_OR_NEWER
                if (webRequest.result == UnityWebRequest.Result.Success)
#else
                if (string.IsNullOrEmpty(webRequest.error))
#endif
                {
                    encryptData = webRequest.downloadHandler.data;
                    if (secretKey != null)
                    {
                        for (int i = 0; i < encryptData.Length; i++)
                        {
                            encryptData[i] = (byte)(encryptData[i] ^ secretKey[i % secretKey.Length]);
                        }
                    }
                }
                else
                {
                    encryptData = null;
                }
            }
            return encryptData;
        }
        
        /// <summary>
        /// 获取解密的数据(无密钥的情况下直接获取数据)
        /// </summary>
        internal static byte[] GetDecryptData(string filePath, char[] secretKey = null)
        {
            byte[] encryptData;
            using (UnityWebRequest webRequest = UnityWebRequest.Get(filePath))
            {
                webRequest.SendWebRequest();
                while (!webRequest.isDone) { }
#if UNITY_2020_1_OR_NEWER
                if (webRequest.result == UnityWebRequest.Result.Success)
#else
                if (string.IsNullOrEmpty(webRequest.error))
#endif
                {
                    encryptData = webRequest.downloadHandler.data;
                    if (secretKey != null)
                    {
                        for (int i = 0; i < encryptData.Length; i++)
                        {
                            encryptData[i] = (byte)(encryptData[i] ^ secretKey[i % secretKey.Length]);
                        }
                    }
                }
                else
                {
                    encryptData = null;
                }
            }
            return encryptData;
        }
        
        /// <summary>
        /// 得到一个路径下文件的大小
        /// </summary>
        public static long GetFileLength(string filePath)
        {
            long fileLength;
            using (FileStream fs = new FileStream(filePath, FileMode.Open))
            {
                fileLength = fs.Length;
            }
            return fileLength;
        }
        
        private static readonly UInt32[] CRCTable =
        {
          0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
          0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
          0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
          0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
          0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
          0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
          0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
          0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
          0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
          0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
          0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
          0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
          0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
          0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
          0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
          0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
          0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
          0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
          0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
          0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
          0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
          0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
          0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
          0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
          0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
          0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
          0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
          0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
          0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
          0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
          0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
          0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
        };
        
    }
}